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Патент USA US3093210

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June 11, 1963
Filed June 27, 1958
United States Patent O?ice
Zdenek Kadlec and Miloslav Lebeda, Prague, Czecho
slovakia, assignors to Meopta-Praha, narodui poduik,
Prague, Czechoslovakia
Filed June 27, 1958, Ser. No. 745,146
Claims priority, application Czechoslovakia Sept. 25, 1957
Claims. (Cl. 177-157)
Patented June 11, 1963
of free end portions of the arresting member 5 by means
of adjustable abutments 10, 11 mounted on a horizontal
cross beam 18 fastened to the top of the rod 9, said ar
resting member being adapted to lift a substantially hori
zontal beam 20 with center knife edge 21 and compen
sating suspensions (not shown) by means of threadedly
adjustable stop members .12, '13 from the operative posi
tion illustrated in FIG. 1. The stop members ‘12, 13 are
mounted on the tWo free ends of the arresting member 5.
FIGS. 3, 4 and 5 show another embodiment of the
This present invention relates to an arrestment ar
arresting device. The arresting member ‘5’ has an elas
rangement for a precision balance and the like.
Precision balances are arrested by lifting the center
tically ?exible central portion 15 which is immovably se
knife edge of the beam from the supporting knife edge
bearing. All known types of arresting mechanisms have
16, 17 between which the knife edge bearing 2 is ?xedly
the common feature that the member of the arresting
mechanism directly actuating the beam is movably
mounted on a rotatable pivot or in a bearing for sliding
movement. In order to secure smooth arresting move
ment it is necessary to provide the movable mounting
with an initial play which increases in operation due to
the wear of the components. The center knife edge of
the beam comes to rest on a different portion of the cor
cured to the head 1 by means of divided cylindrical bolts
fastened to the head 1. The free end portions of the ar
resting member 5’ pivot about axes 6’ and 7'. These
axes are spacedly adjacent the pivot axis of the beam 20
and substantially parallel thereto. The pivot axis of the
balance beam is de?ned by the line of engagement of the
bearing 2 by the knife edge 21 and lies substantially in
the median plane of the bearing 2 transverse to the di
rection of elongation of the arresting member 5’.
In both embodiments illustrated, play of the lifting rod
rested beam, with the result that the effective length ratio 25 8 in the bracket 9 is Without effect on the beam. The
arresting member may be made of elastic material with
of the arms of the beam as well as the position of the
responding bearing or plane after each release of the ar
zero point are changed.
It is an object of the invention to ensure the steadiness
of the mutual position of the center knife edge of the
beam and of the corresponding bearing, irrespective of
the play in the arresting mechanism. This is achieved,
according to the invention, by interposing an arresting
member between that portion of the arresting mechanism
which is movably mounted on the stationary portion of
the balance and the beam. The arresting member of the
invention is irnmovably mounted with respect to the cen
ter knife edge bearing. This member forms an arresting
support which is elastically ?exible in its central portion
which is adjacent to the pivot of the center knife edge.
In practice it is easier to make the arresting support elas
tically ?exible at two points situated as closely as pos
sible to the pivot axis of the center knife edge and sym
metrical thereto.
The accompanying drawing shows by way of example
portions of reduced cross section where ?exibility is de
sired as at ‘6 and 7 in FIG. 1. The arresting member
may be formed by pressing, extrusion or the like. Con
versely, the arresting member may be shaped so as to be
?exible throughout the length thereof, and those portions
which need not be ?exible may be reinforced by suitably
pro?led reinforcing members. It is further possible to
make the arresting member of elastic and inelastic por
tions rigidly assembled by screws, rivets, by soldering or
the like, and in this case the elastic portions will be lo
cated in the pivot areas, or a combination of the two
aforesaid arrangements may be employed.
We claim:
1. An arrestment arrangement for a precision balance
and the like, comprising a support, a bearing ?xedly
mounted thereon, a balance beam movable in an upward
direction ‘from an operative to an arrested position, and
vice versa, knife edge means on said balance beam en
two embodiments of the arrestment arrangement accord 45 gaging said bearing, when in said operative position, for
ing to the invention.
FIG. 1 shows in a diagrammatic elevational view the
arrangement of the arresting mechanism,
FIG. 2 is a partial plan view of the apparatus of
FIG. 1,
FIG. 3 shows in a plan view a modi?ed arrangement
of the central portion of the mechanism,
FIG. 4 is a cross sectional view drawn to enlarged scale
along the line 4—4 of FIG. 3, and
FIG. 5 is a cross sectional view drawn to enlarged
scale along the line 5——5 of FIG. 3.
As seen in FIGS. 1 and 2, a center knife edge bearing
2 is ?xedly mounted on a head 1 of a balance column,
pivoting support about an axis extending transversely to
the elongation of said beam, an elongated arresting mem
ber having a center portion ?xedly fastened to said sup
port, two opposite free end portions, and at least a single
elastically ?exible portion permitting simultaneous equi
directional arcuate movements to and from an arresting
position of said free end portions about at least a single
axis extending transversely to the elongation of said ar
resting member, abutment means on said free end por~
tions, said abutment means supporting said balance beam
when said end portions are moved to said arresting posi
tion, and means for actuating said arresting member to
cause said a-rcuate movements of said ‘free end portions.
2. The arrestment arrangement according to claim 1,
not otherwise shown. An elongated arresting member 5 60
wherein said single elastically ?exible portion of said ar
is centrally fastened to the head v1 by screws 3, 4 and is
resting member is constituted by said center portion
elastically ?exible or pivotable at ‘6 and 7. A lifting rod
8 is mounted on the balance column for vertical sliding
3. The arrestment arrangement according to claim 1,
movement in a bracket 9 and actuates ?exing movements
wherein said arresting member has two elastically ?exible
portions, each of said ?exible portions connecting said
center portion and one of said free end portions.
4. In the arrestment arrangement according to claim
1, said actuating means including a bar member recipro
cally slidable on said support in vertical directions, and
additional abutment means on said bar member adapted
to abut against said free end portions and to cause the
arcuate movements thereof, and thus to cause said ?rst
References Cited in the ?le of this patent
Becker ______________ __ Ian. 24,
Germany ____________ _- Oct. 29,
named abutment means to carry out said movements of 10
said balance beam and to support said balance beam
when in said arrested position.
Seyter ______________ __ July 23,
Weckerly ____________ __ Feb. 5,
Mettler et a1. ________ __ Aug. 11,
Sartorius _____________ -_ Mar. 8,
Wagner _____________ __ Sept. 29‘,
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